fix(historian-sidecar): don't wedge the TCP listener when Start() bind fails

Live verification on a Windows VM surfaced a crash loop: TcpFrameServer.EnsureListening
assigned _listener = new TcpListener(...) BEFORE calling Start(). When Start() throws —
e.g. the port is in a Windows excluded/reserved range (WSAEACCES) or already in use — the
field was left non-null-but-unstarted, so the `if (_listener is not null) return` guard
permanently skipped re-Start() and every subsequent AcceptTcpClientAsync() threw the
misleading InvalidOperationException "Not listening" → 20 failures → exit 2 → NSSM restart
→ loop. Now _listener is assigned only after Start() succeeds, so a transient bind failure
is retried and a permanent one surfaces the real bind error each iteration. Adds a
regression test that forces a bind conflict and asserts the SocketException persists.

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware/Ipc/TcpFrameServer.cs

@@ -48,8 +48,16 @@ public sealed class TcpFrameServer : IDisposable
     private void EnsureListening()
     {
         if (_listener is not null) return;
-        _listener = new TcpListener(_bind, _port);
-        _listener.Start();
+
+        // Assign _listener ONLY after Start() succeeds. If Start() throws (e.g. the port is in
+        // a Windows excluded/reserved range → WSAEACCES "access forbidden", or already in use),
+        // _listener must stay null so the next RunAsync iteration retries the full create+Start.
+        // Assigning before Start() leaves a non-null-but-unstarted listener that the
+        // `if (_listener is not null) return` guard would never re-Start, turning a one-time
+        // bind error into a permanent misleading "Not listening" crash loop.
+        var listener = new TcpListener(_bind, _port);
+        listener.Start();
+        _listener = listener;
     }
 
     /// <summary>